US 7377895 B2
A system for use in conducting coronary surgery permits coronary surgery on a beating heart while maintaining cardiac output unabated and uninterrupted. Circumflex coronary artery surgery can be performed using the system. The system includes a first device for engaging and repositioning the beating heart to a displaced position, and is capable of maintaining the heart in the displaced position to perform a surgical procedures. The system includes a second device adapted to engage a portion of the heart to immobilize that portion for conducting a surgical procedure in the immobilized location, while the remainder of the heart continues to beat. Both first and second devices may be adapted to be fixed to a relatively stationary object, such as a frame, which may be a sternal retractor.
1. A system for use during coronary surgery on a beating heart, comprising:
a suction head adapted to positively engage the beating heart;
an arm which is flexible in an unlocked condition and rigid in a locked condition;
a spring suspension connecting said suction head to said arm; and
a surgery target immobilizing element adapted to contact a portion of the heart to immobilize the location of the heart on which the surgery is being performed.
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22. A system for use during coronary surgery on a beating heart, comprising:
a suction head adapted to engage a region of the heart;
an arm which is flexible in an unlocked condition and rigid in a locked condition;
a suspension mechanism connecting said suction head to said arm;
an attachment mechanism adapted to fix said arm to a relatively stationary object, wherein said suction head is free to move, relative to said arm via said suspension mechanism, even when said arm is in said locked condition; and
a surgery target immobilizing device adapted to contact a portion of the heart to immobilize the location of the heart during performance of the surgery.
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39. A system for use during coronary surgery on a beating heart, comprising:
a first device configured to engage and reposition the beating heart to a displaced position and maintain the heart in the displaced position while allowing cardiac output to be maintained substantially unabated and uninterrupted, said first device having an engaging portion adapted to engage the heart and a proximal portion configured to be fixed relative to a relatively stationary object, wherein said engaging portion moves with movements of the beating heart, while maintaining the beating heart in the displaced position, when said proximal portion is fixed; and
a second device adapted to engage a portion of the heart to immobilize the portion, while a remainder of the heart continues to beat, to facilitate surgery in the location of the portion of the heart.
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a suspension mechanism connecting said suction head to said arm; and an attachment mechanism adapted to fix said arm to the a relatively stationary object, wherein said suction head is free to move, relative to said arm via said suspension mechanism, even when said arm is in said locked condition.
The present application is a continuation of U.S. application Ser. No. 09/956,418 filed Sep. 18, 2001, now U.S. Pat. No. 6,743,170, which issued on Jun. 1, 2004, which is a continuation of U.S. application Ser. No. 09/087,511 filed May 29, 1998 which is now U.S. Pat. No. 6,338,712, issued Jan. 15, 2002, which is a continuation-in-part application of application Ser. No. 08/936,184 filed on Sep. 17, 1997, which is now U.S. Pat. No. 6,019,722, issued Feb. 1, 2000. U.S. application Ser. Nos. 09/956,418; 09/087,511 and 08/936,184 and U.S. Pat. Nos. 6,743,170, 6,338,712 and 6,019,722 are hereby incorporated by reference thereto, in their entireties.
The present invention relates to the general art of cardiac surgery, and to the particular field of heart retractors used in beating heart surgery.
There are as many as 300,000 coronary bypass graft procedures performed annually in the United States. Each of those procedures may include one or more graft vessels. Currently, each graft vessel must be hand sutured. As many as four or more grafts are placed in a procedure. Until recently, coronary artery bypass procedures have been performed with the patient on cardio-pulmonary bypass whereby the heart is stopped with cardioplegia and the surgery performed on an exposed and still heart.
Some pioneering surgeons are performing procedures in which the coronary bypass is performed on a beating heart. That is, without heart-lung bypass and cardioplegia. This minimizes the time it takes to perform the procedure and reduces the cost of the operation by eliminating the heart-lung bypass machine.
Coronary Artery Bypass Grafting (CABG) is performed and a new blood supply to the heart muscle is established when coronary arteries are blocked with calcium or plaque. A new blood supply conduit is joined to the diseased coronary, distal to the blockage, thus providing a fresh supply of oxygenated blood to the vessel in question. Today, this is accomplished by hand suturing a graft vessel (the new supply of blood) to the diseased vessel. This junction is called an anastomosis of vessels. Many different types of supply conduits can be used. Examples are cadaver vein, saphenous vein, radial artery, internal mammary artery, and the like.
By way of background, the basic operation of a heart will be briefly discussed. The heart works like a pump. The left and right ventricles are separate but share a common wall (the septum). The left ventricle is thicker and pumps the blood into the systemic circulation. The work it performs is much greater than the right ventricle. The right ventricle pumps blood into the pulmonary circulation, which is a low pressure circuit. The left ventricle wall (a low energy system) is much thinner than the right ventricle.
The left ventricle fills in diastole and ejects in systole. The difference between the diastolic volume (largest) and the systolic volume (smallest) (the stroke volume or amount of blood ejected on each heartbeat) multiplied by heart rate determines the cardiac output of the heart (liters/min. of flow). The heart shortens during systole as the muscle contracts. There are a number of motions during contraction (including a considerable amount of rotation) but for practical purposes the heart can be thought of as a truncated cone. Shortening occurs along its length and also along its diameter. For purposes of this disclosure, the more important of the two motions is the shortening along the diameter since the ejection volume varies as the square vs. along the length which varies with the first power.
The heart functions well whether the person is upright, upside down, prone or supine. It sits inside the pericardium—a sac which limits its motion and spreads the support on the heart so that no matter how a person positions himself, it is not particularly compressed and is able to fill and then eject with each heartbeat. The concept of the pericardium spreading the load is critical, i.e., when lying supine, the posterior pericardium supports the heart over a large surface of the heart just as when the person is lying on his stomach, the front of the pericardium spreads the load.
When the chest is opened by a median sternotomy it is possible to gain access to all chambers and surfaces of the heart. This combined with the fact that this incision is usually less painful than a thoracotomy (rib separation), makes this the preferred surgical approach to the heart.
The coronary vessels are surface vessels, only occasionally dipping into the myocardium making them accessible without opening the heart. Traditionally, bypass surgery is done with the heart arrested. This stops the motion of the heart and allows the arrest of the coronary circulation so the surgeon sews in a bloodless and easy to see field. Since the heart is stopped, the patient would suffer irreversible damage to the brain and other tissues and organs without the use of the heart-lung machine to support the general circulation. Although the heart-lung machine has been refined, it is particularly toxic to older and debilitated patients and it is expensive.
It is possible to perform surgery off bypass, while the heart is beating and the coronaries are under positive blood pressure; however, there may be problems. One problem is that not all vessels are accessible since some vessels are on the posterior or inferior surfaces and that when such vessels are brought into view by lifting the heart, cardiac performance is impaired such that the cardiac output falls and blood pressure drops. A second problem is that the heart moves so that suturing in vessels (12 to 15 stitches in a vessel under 2 mm in diameter) might be inaccurate and a third problem is that there is blood in the field as the coronary circulation is not interrupted. This last problem is now largely solved by snares, which temporarily stop the flow of blood through the targeted arteries. The problem of lifting the heart is not to impair the performance of the heart while at the same time adequately exposing the heart and regionally immobilizing the vessel during beating heart surgery, and this problem is not solved with any prior art system.
For the heart to be effective, it must have adequate biventricular function (both right and left ventricles). The left ventricle pumps into the high resistance systemic circulation and is thicker and generates considerably more energy than the right ventricle. It is primarily circular in cross section. This displacement of blood (and thus heart output) depends on shortening in the short axis (diameter of the cross section) and to a lesser degree on shortening in the long axis (apex to base). There is also rotational motion to the heart as it contracts, thus imparting multiplanar motion to the heart as it beats; still further, the surface of the heart undergoes multiplanar movement during operation of the heart. The right ventricle pumps into the lower resistance pulmonary circulation and is much thinner and its energy generation is much less than that of the left ventricle. Function of both of these ventricles must be maintained during surgical manipulation of a beating heart.
Therefore there is a significant need for a means and a method for moving a beating heart so as not to impair the performance of the heart while at the same time adequately exposing the heart and regionally immobilizing a vessel during beating heart surgery.
Lifting of the heart is deleterious to heart function for several reasons. First, the lifting of the heart impairs the venous return to the heart so that there is less diastolic filling of the heart (this can largely be corrected by putting the head down and the feet up to increase venous return). Second, the heart is distorted. Using a hand or spatula to lift the heart is quite different than simply changing body position when the heart is inside the chest. The force applied by the hand to the heart is localized so that the heart is no longer a truncated cone, but is much flatter. This shape is much less effective for ejection (the circle is the most effective as it has the highest ratio of volume to diameter) and flattening also limits the diastolic volume so that inadequate filling occurs. Third, lifting pressure applied to a beating heart may deleteriously affect valve function of the heart, in particular, the mitral valve function may be adversely affected by such lifting.
In order to perform cardiac surgery on a beating heart, there is a need to lift, support and orient the heart without reducing its ability to function. Therefore, there is a need for a means and method to move and orient a beating heart into position so any vessel of the heart can be accessed without unduly interfering with the operation of the heart, especially the mitral valve function.
In coronary bypass operations, grafts have to be anastomosed to the anterior descending artery (right coronary artery branch), the circumflex artery, and to the posterior descending artery. The anterior descending artery lies on the front surface of the heart and is easily accessible to the surgeon without particular help from surgical assistants or using any devices. The circumflex and posterior descending arteries, however, lie on the back surface of the heart. Therefore, to expose the circumflex artery to a field of view of the surgeon, it is mandatory to lift the heart and rotate it about the axis of the inferior vena cava and the superior vena cava. Likewise, to expose the posterior descending artery, it is necessary to lift the heart and rotate it in the direction of its apex. If the heart is moved improperly, it may go into fibrillation.
Ordinarily, a surgical assistant is employed to lift the heart by using his or her hand, this is satisfactory for an arrested heart. However this is not satisfactory for a beating heart. However, it is very difficult and tiring to keep the heart in a steady position. Furthermore, the myocardium in contact with the assistant's fingers may be damaged by pressure, avulsion, and premature rewarming. Further, the assistant's hand in the operative field can get in the way, and the assistant, who often stands next to the surgeon may restrict the surgeon's movements.
To date, with the exception of the device disclosed in the parent application, devices that have been directed toward facilitating beating heart surgery have been very simple stabilization platforms. A two-tined fork is the simplest and works well on directly exposed vessels such as the LAD. Another device is comprised of a hollow support tube which can be clamped outside the patient's body cavity. The support tube terminates in a suction head with a number of suction ports arranged in a linear row in such a way that they resemble the suction cups of an octopus. These suction heads are attached to the myocardium and ideally allow the heart to be regionally immobilized on either side of the target artery. This allows for a very localized stabilization of an artery to perform an anastomosis. This tool accomplishes the requirements for immobilizing the target artery for surgery. However, this tool is inadequate for actually lifting the heart to gain access to vessels located on the posterior and lateral surfaces (circumflex and right coronary distributions). This device really is a local stabilizer, and cannot be adequately employed to assist in the lifting or moving of the heart, which is necessary in some instances, such as for a large heart, or the like. However, it has also acquired another role, that of vessel presentation. Unfortunately, the device was not implicitly designed for this function. Vessel presentation during beating heart surgery is a different function and more complex since it must allow the entire heart to function. Yet it is the more commercially valuable application of this tool since there are no other mechanical stabilizers available which are simple and acceptable to lift the functioning heart to access all vessels and eliminate the need for cardio-pulmonary bypass.
Therefore, there is a need to provide a tool that is commercially viable and which can be used for vessel presentation, and which can be used to assist in lifting and/or orienting the heart when needed.
The surgeon would like a very localized, immobilized area, such as one to two cm, on either side of the target vessel. The above-mentioned tool immobilizes the heart transmurally for a distance of two to 3 cm on each side. Small suction heads, like the surgeon prefers for local immobilization, unfortunately cannot lift the heart and larger suction heads impair heart function by immobilizing too large an area around the suction head. If several rigid heads are used circumferentially around the heart in order to lift it, a large amount of the heart is prevented from contraction. This will immobilize too much of the heart circumference to maintain effective heart function.
Therefore, there is need for a means and method for immobilizing a particular area on the heart without unduly interfering with the functioning of the heart, and which can be used to lift the heart as well, again, without interfering with the operation of the heart. There is also a need for a system for manipulating a heart during cardiac surgery which will support the heart in position for coronary bypass surgery of the circumflex coronary artery and posterior descending artery.
Still further, the myocardium of a beating heart undergoes multiplanar movement and motion during operation of the heart. A suction cup applied to such a moving surface may have a tendency to become separated from the myocardium thereby interrupting the suction being applied to the heart. Such interruption of suction may interfere with the attachment of the device to the heart.
Therefore, there is a need for a means and method for manipulation of a heart during cardiac surgery that will not be impaired by movement of the myocardium during operation of the heart.
One remedy for this problem is to make the suction cups larger. However, this is not practical since too much of the myocardium might be influenced by such a solution.
Therefore, there is a need for a means and method for manipulation of a heart during cardiac surgery that will not be impaired by movement of the myocardium during operation of the heart, while influencing a minimum amount of the myocardium.
Another prior art method of supporting a heart is by use of a sling. A sling is a network of fabric or plastic that is placed around the heart in the manner of a hammock. The heart is then supported by the sling. It is noted that in order for a sling to work as a retractor, the surgeon is required to arrange the ties to be pulled from the proper direction, such as normal to the desired direction of lift, which can be onerous. This presents a serious problem since there are no easy reference points above the patient in which to attach these ties.
While the art has included several inventions intended to support the heart during coronary bypass surgery of the circumflex coronary artery, these inventions have several drawbacks that have hindered their acceptance in the art. For example, the use of nets to support the heart exposes the heart to fine strands which impinge on the heart and may cause damage. Furthermore, nets may impede the surgical target and require special techniques or procedures to remove the net from the surgical target area. This is especially onerous if the net mesh is fined. Flat cloth tapes are a form of net, and may damage the heart due to a rough texture of the cloth and the small area of contact between the tape strands and the heart. Further, tapes and similar devices that do no have large surface areas contacting the heart may not support the heart in a uniform manner and may create large pressure areas at the contact points.
Therefore, there is a need for a manipulation system for use in cardiac surgery which will support the heart in position for coronary bypass surgery of the circumflex coronary artery in a manner that will not damage the heart yet will provide easy access to the surgical target and keeps working while cardiac output is maintained.
Still further, some prior art means for supporting the heart during cardiac surgery may tend to interfere with ventricle operation.
Therefore, there is a need for a means and a method for manipulating a heart during cardiac surgery which will not interfere with ventricle operation of the heart while a beating heart is supported in position and orientation for surgery.
The parent disclosure discussed a means and method for lifting the heart during surgery. This means and method included a gross support means for engaging the apex portion of the heart and which is fixed to a stationary element, such as the operating table or the like. The preferred form of the gross support means includes a cup-shaped element that fits around the apex of the heart to support the weight of the heart and which is attached to a source of suction.
The means and method disclosed in the parent disclosure work well, but the inventors have since discovered that it would be beneficial to the overall success of beating heart surgery to contact the least amount of myocardium as possible in moving the heart for surgery.
A further consideration in coronary artery surgery is hemorrhage from the incision into the coronary artery at the proposed anastomotic site. Therefore, heretofore, coronary artery surgery has been carried out under conditions of cardiac arrest and aortic root cross clamping. Hence, the myocardium is temporarily deprived of coronary blood supply. In some patients, an additional coronary blood supply, through the form of bronchial circulation, causes significant hemorrhage during the bypass grafting process. This hemorrhage is inconvenient, as it masks the surgeon's view during the delicate suturing process, and threatens the well-being of the patient. Performing surgery in this manner has several additional drawbacks, including the need to stop the heart, the need to insert special equipment and procedural steps to carry out the function of moving blood through the patient's body while the heart is stopped.
Therefore, there is a need for a heart retractor which will support the heart in position for coronary bypass surgery of all of the coronary arteries, including the circumflex coronary artery, in a manner such that the tool does not damage the heart while cardiac output is maintained yet will provide easy access to the surgical target and which can be used in a manner that does not require the heart to be stopped.
Still further, there is a need for a system for manipulating the heart during cardiac surgery which permits regional as well as specific immobilization of the heart.
However, the continued operation of the heart will produce problems, in addition to the above-discussed problems, of forming a moving target for the surgeon. That is, since the heart continues to beat during the operation, the surgical target will move in connection with such beating movement. The heart cannot be stopped or unduly constrained without increasing the danger of fibrillation.
Therefore, there is a need for a system for manipulating the heart during cardiac surgery which will support a beating heart in position for coronary bypass surgery of coronary arteries in a manner that will not damage the heart yet will provide specific and regional support while allowing unabated cardiac output.
Recently, there has been interest in minimally invasive coronary bypass surgery. This is not surprising since a median sternotomy and a run on the cardiopulmonary bypass pump are not well tolerated by some patients, combined with the added cost of coronary bypass equipment and staff. The procedure results in considerable recovery time and is associated with a risk of death and major complication. While the ultimate goal is to provide bypass to all vessels by port access (like gallbladder surgery) and to eliminate the need for cardiopulmonary bypass, a more limited but reasonable option for the next number or years will be to perform bypass off pump with an incision (sternotomy or thoracotomy). A tool which could allow performance of multivessel off pump bypass would be most helpful.
Therefore, there is a need for a heart retractor which will support the heart in position for minimally invasive coronary bypass surgery of coronary arteries, including the circumflex coronary artery, in a manner that will not damage the heart yet will provide easy access to the surgical target without requiring the heart to be stopped yet without unduly constraining the heart.
Still further, the inventors have observed that not all hearts are the same size, shape and have the same spacing between corresponding areas. Thus, while all hearts are basically the same, there may be a variation between individual hearts. Therefore, a device that supports a heart should account for these variations. This is especially true if the heart is to continue pumping during the operation and while it is supported. If the support is not fit to the particular heart, it may constrict the heart in some manner and thus interfere with the continued output of the heart.
Therefore, there is a need for a system for manipulating a heart during cardiac surgery which will support a heart, especially a beating heart, during cardiac surgery and which can be adjusted to fit the particular needs of the individual heart and will support the heart both in gross and regionally.
It is main object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support the weight of a beating heart and maintain cardiac output unabated and uninterrupted even though the heart is maintained in an unnatural position and/or orientation.
It is another object of the present invention to improve the retractor disclosed in the parent disclosure.
It is a further object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support a beating heart in position for coronary bypass surgery and which can support the heart both regionally and in gross.
It is a further object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support a beating heart in position for coronary bypass surgery and which can support the heart both regionally and in gross and which can account for variations in individual hearts.
It is a further object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support a beating heart in position for coronary bypass surgery of the coronary arteries, including the circumflex coronary artery.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support the heart in position for coronary bypass surgery of the coronary arteries in a manner that will not damage the heart yet will provide easy access to the surgical target.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support the heart in position for coronary bypass surgery in a manner that will not damage the heart yet will provide easy access to the surgical target and which can be used in a manner that does not require the heart to be stopped.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which can support the heart while maintaining competent mitral valve function.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support the heart in position for coronary bypass surgery in a manner that prevents collapse of the right ventricle during manipulation of the heart.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support the heart in position for coronary bypass surgery in a manner that will not damage the heart yet will provide easy access to the surgical target without requiring the heart to be stopped yet without unduly constraining the heart.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which will support the heart in position for minimally invasive coronary bypass surgery in a manner that will not damage the heart yet will provide easy access to the surgical target without requiring the heart to be stopped yet without unduly constraining the heart.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which will provide regional and specific immobilization of the heart.
It is another object of the present invention to provide a system for manipulating a heart during cardiac surgery which will isolate one region of the heart while allowing cardiac output to be sustained.
These, and other, objects are achieved by a system for manipulating a heart during cardiac surgery which suspends the heart from the apical region near the right ventricle and prevents collapse of the right ventricle during the manipulation. The heart can be supported by this suspension, but also has a gross support that is located near the left ventricle and extends along the arterialventricular (AV) groove to lift and rotate the heart while supporting the mitral valve annulus to maintain competent valve function of the mitral valve. Two-point support can thus be provided in a manner that maintains cardiac operation unimpeded. Still further, the system can include a surgical target immobilizing means that is, itself, capable of assisting in the lifting of the heart under some circumstances and thus can be used to assist in the movement of the heart during cardiac surgery. The location and design of the elements of the system of the present invention achieves the lifting and orienting of the heart in a manner that presents the heart in the most advantageous position and orientation for surgery while permitting the heart to maintain cardiac output in an essentially unabated manner. This provides a stationary target for the surgeon while supporting the heart in a safe manner and in a manner that does not interfere with the surgeon or his field of sight. In this manner, the system of the present invention can be used to support a heart during cardiac surgery without requiring an assistant to hold the heart, yet will permit the surgical procedure to be carried out without requiring cardiac arrest.
Furthermore, the system of the present invention includes a frame that is located within the patient's thoracic cavity whereby movement of the patient automatically moves the heart supporting elements in a corresponding manner. This maintains the surgical work field clear and automatically repositions and reorients the heart supporting elements as the patient is moved. This efficiently keeps the heart supported during surgery.
More specifically, a first form of the system for manipulating a heart during cardiac surgery includes an element that can be cup-like and which has a flexible rim that engages the myocardium of the heart in a manner that maintains the engagement even while the myocardium moves during heart operation. Still further, the cup-like element is designed so that heart tissue will not interfere with the operation of the element. The cup-like element applies suction to the heart to hold the element associated with the cup-like element on the heart. The cup-like element is used in connection with the suspension head discussed above as well as in connection with the surgery target immobilizing element. Flexible means on the cup-like element permit that element to move to accommodate multiplanar movement of the heart during operation of the heart. Still further, the gross support means may also use suction to hold the support against the heart. If used, the suction interface is designed so heart tissue will not interfere with the suction applied via the gross support means. The design of the suspension head, the suction cups and the surgical target immobilizing means is such that the system of the present invention can accommodate an individual heart and is amenable to use on hearts of different sizes, weights and even locations. In this manner, a heart, especially a beating heart, can be supported in the manner that is most effective for that particular heart. Thus, in the case of a beating heart, cardiac output can be maintained in an unabated and uninterrupted manner as there will be virtually no constrictions on the heart because the support will be perfectly fitted the particular heart.
A form of the system of the present invention can be used in minimally invasive surgery. The system may include a handle on the gross support means to move the gross support means as required, and a handle can be placed on the target-immobilizing means to move that means as necessary as well. The distal ends of the handle are located to provide access to the handle while remaining unobtrusive during surgery. Detachable handles could also be used whereby the handles are removed after correct placement of the head.
While this invention is disclosed in the preferred form for open chest procedures for beating heart surgery, it may also be utilized for minimally invasive procedures as well as those that use cardioplegia due to its novel time saving and enabling features. It is also noted that this disclosure is not directed to the art of anastomosis per se. However, it is directly related to enabling a surgeon to perform an anastomotic procedure in a precise and controlled manner.
The inventive device disclosed herein eliminates the need for use of the heart-lung machine. It allows a surgeon to lift and displace the heart to expose all vessels to regionally immobilize them for suturing without seriously impairing heart performance.
The advances made using the retractor disclosed in the parent disclosure are thus improved.
Once the stabilization of the beating heart has been achieved as with the system of the present invention, it then becomes more feasible to entertain the idea of performing this surgery in a minimally invasive manner precluding the need for the median sternotomy.
By way of introduction, the operation of a heart will be discussed before describing the system embodying the present invention. In
Cardiac contraction is orchestrated by electrical impulses originating from the heart's nervous system. Electrical stimulation to the myocardial fibers results in muscular contraction. Specifically timed electrical signals originating in the upper chambers of the heart cause the atriae to contract and empty blood into the ventricles 16 and 30. After atrial contraction, a short electrical delay takes place. This pause allows the ventricles 16 and 30 to receive blood from atriae before they are stimulated to contract. With ventricular contraction, blood is ejected from heart 10.
By way of further introduction, the retractor disclosed in the parent disclosure will be briefly discussed. The retractor disclosed in the parent disclosure clamped the heart in a manner that restricts the length dimension while permitting the other dimensions to change. By immobilizing the heart in a direction along dimension L, but allowing the remainder of the heart to operate in a normal manner, operation of the heart is not restricted. The retractor of the present invention further immobilizes only the specific surgery target area whereby the remainder of the heart operates in an unrestricted manner. Thus, only the specific surgery location is immobilized. This is all that is required for a successful surgery and the entire heart need not be immobilized. The system for manipulating a heart during cardiac surgery of the present invention also lifts the heart in a manner that permits unrestricted operation of the heart as well.
Since the present invention is an improvement over the parent disclosed invention, it will be instructive to briefly review that parent retractor. Further discussion of the parent retractor can be found in the parent disclosure which is incorporated herein by reference. Referring specifically to
The retractor of the parent disclosure further includes a fine support means for immobilizing selected portions of the heart while permitting non-immobilized portions to move in a manner that continues heart operation. This fine support means includes a plurality of rigid arms 80 each being fixed at one end thereof to anchor 68 and having a heart-attaching element 82 thereon, such as at the outer end thereof. As used herein, the term “rigid” is a relative term and means that the arms are rigid enough whereby the force of the heart won't move them. But they can be adjustable such as being formed of a wire-wound gooseneck or soft metal which allows each arm to be individually shaped according to the needs of the attachment location. The heart-attaching elements can be suction attachment points such as suction cups that are fluidically connected to manifold 70. Other means of attaching the elements to the heart, can be used as well without departing from the scope of the present disclosure as will occur to those skilled in the art based on the teaching of this disclosure. Examples of other such elements include glue, sutures, clamps, shallow pins, pincers or the like, with attachment points being located on the arm as suitable. The rigid arms secure small or fine areas of the heart in place with respect to gross element 52 while permitting the heart to move as required to continue unabated cardiac output. Support means 50 further includes a plurality of flexible support arms 84 each fixed at one end thereof to anchor 68 and having a heart-attaching element 86 on the outer end thereof. Elements 86 can be suction elements similar to the just-discussed elements 82. Flexible arms 84 can be adjusted to secure the heart in the most advantageous locations whereby the heart can continue to operate without undue restriction.
Therefore, broadly, the overall parent retractor comprises a main support which includes the arms, the hub and a stationary member, such as a table top, the floor or the like; a gross support which includes the apex cup and fine support means which regionally immobilizes portions of the heart while leaving other regions of the heart free to operate in an unabated manner to maintain heart output during the surgical procedure. The fine support means can include the rigid arms as well as the surgery target immobilizing means. In this manner, the heart is supported regionally yet operates to maintain blood flow during coronary surgery.
As was discussed in the parent disclosure, during operation of the heart, the left ventricle is a conical shaped cavity which is narrowest at the apex. It shortens both in length and in diameter during a pumping stroke (contraction). Since the volume of blood displaced is more dependent on the reduction in diameter (square) than the shortening in length (first power), any measure which reduces the shortening of the diameter is very detrimental. Also, the right ventricle is attached to the left ventricle and is considerably thinner and less powerful. Suction attachments to this part of the heart which would impede the shortening of muscle may be poorly tolerated. The invention disclosed and taught herein uses a series of linked attachments to the heart. Attachments which are near the artery to be bypassed are paired on opposite sides of the artery and do not move—they immobilize the artery and therefore the muscle in the target region. A lifting suction is applied at the apex of the heart. If this were the only site of lifting, the heart would be stretched and there would be no diameter left. Thus, no blood could be ejected. However, this invention adds additional heart attaching elements that are attached to the heart to lift it. These attachment points would be mobile in that they could allow the heart to move inward and reduce the diameter and eject blood. The key to the invention is the linking of lifting (both at the apex and around the circumference of the heart) and regional immobilization which stops one part around the circumference from moving and therefore allows easy suturing.
As discussed above, while the parent retractor works well, it can be improved. Referring to
The heart manipulation system of the present invention utilizes a special suction cup to attach various elements thereof to the beating heart in a manner that permits the heart and the myocardium to move during heart operation without unduly affecting the attachment of the element to the heart. Specifically, the suction cup of the present invention applies suction to the heart surface from a source of suction (not shown, but discussed in the parent disclosure). Suction cup 200 of the present invention is best shown in
However, suction cup 200 shown in
As can be understood from
Suction cup 200 is the best mode used in the present invention; however, other forms of suction cups can be used without departing from the scope of the present invention and disclosure. The other forms of the suction cup will also have at least one first chamber and one second chamber and a flexible rim as well as a mesh grid element preventing tissue from interfering with suction applied via the suction cup. Other forms of the suction cup are indicated in
Mesh grid element 210 functions to preserve suction pressure on the tissue even if the tissue is drawn into the suction cup. Thus, mesh grid element 210 has a first portion that can be engaged by the tissue, and a second portion that will remain open even when the first portion is engaged by tissue. An example of such a mesh grid element is shown in
As will be evident to those skilled in the art based on the teaching of the present disclosure, this flexible rim multi-chamber suction element with a mesh grid element will be used in those elements of the heart manipulation system of the present invention that engage the heart to apply force to the heart to move and manipulate that heart during cardiac surgery.
A heart manipulation system 300 for use in cardiac surgery is broadly shown in
Frame 302 includes a cross bar 303 that has a multiplicity of teeth 303T thereon for a purpose that will be understood from the following disclosure. Frame 302 further includes means for engaging the patient to support the frame in position in the patient. A preferred form of this means includes two sternal spacers 304 which set the depth of the frame into the chest cavity and keep the frame from twisting as the lungs inflate and which are connected to cross bar 303 by a ratchet-like mechanism 305 that has teeth which engage teeth 303T when the spacers are in the desired location. The frame is expanded inside the pericardial cavity with the cross bar. A handle 305H is operated to set the teeth of the mechanism 305 to teeth 303T. The frame can be either C-shaped or hoop shaped and can be secured to the patient or to an outside stable support. Other anchor means can be used as well as will occur to those skilled in the art based on the teaching of the present disclosure, and these means are intended to be within the scope of this disclosure as well.
As was the case in the parent disclosure, a source of suction is located outside the patient and is used to attach various elements to the patient's heart. Most often, a source of vacuum is from the operating room source which provides approximately 100 to 180 mm of Hg vacuum. The source of suction is not shown herein as those skilled in the art will understand where such source is best located and what source is best suited to the particular application based on the teaching of the present disclosure.
As shown in
Arm 318 is flexible in one condition as discussed in the parent disclosure, and is made rigid by manipulation of control and anchor element 324. Anchor element 324 includes a base 324A which is movably mounted on cross bar 303 and has internal teeth that engage teeth 303T, and a lever system for locking the internal teeth of element 324 to teeth 303T when desired. A further lever-operated mechanism locks corresponding elements in arm 318 whereby arm 318 is rendered rigid. Arm 318 includes a flexible central line extending from head 314, through flexible element 316 to anchor element 324 and a plurality of relatively movable sections, such as balls 326 interposed between links 328, on the central line. A lever 330 is connected to the central line and when the lever is operated, the elements 326 and 328 are forced together to render the arm rigid. In this manner, the suspension head 314 can be easily maneuvered on a flexible arm into the desired position and then locked into that position by rendering arm 318 rigid. Flexible means 316 permits multiplanar movement of suspension head 314 even after arm 318 is made rigid whereby movement of a beating heart is accommodated by suspension head mechanism 312. When suction is applied to the heart via head 314 the heart will be suspended and can be lifted into the desired position and orientation for cardiac surgery without interrupting cardiac output. The combination of the suction cup, the flexible/rigid arm, the flexible means and the location of the head on the heart effect this result. Various forms of head 314 can be used without departing from the scope of the present invention, and a second form of the head is shown in
With the heart supported by suspension means 312, the cardiac surgery can be completed if desired. As will be discussed below, however, additional support can be provided. Cardiac surgery was discussed above and in the parent disclosure, reference being made thereto for such discussions. As was discussed, a surgery target immobilizer is used to locally immobilize the heart while permitting the non-engaged portions of the heart to continue to operate so as to maintain cardiac output essentially unabated. Shown in
The system of the present invention improves this by including a means 340 for locally engaging a selected section of the heart and locally immobilizing the heart adjacent to a surgery target so the heart is supported by the suspension head mechanism and can receive further support from the surgery target immobilizing means and can thus be free to operate during surgery while it is also locally immobilized at the surgery target with non-engaged sections of the heart free to move in a manner whereby essentially unabated cardiac output is maintained while the heart is locally immobilized. The surgery target immobilizing means 340 of the present invention includes a flexible section 342, such as suction cup 200, on each rigid element SIR. The suction cups 200 attached to each rigid element function and operate as discussed above and shown in
As discussed above, in some circumstances, two point support is preferred when performing cardiac surgery. Accordingly, manipulation system 300 of the present invention provides a gross support means 400 movably mounted on frame 300 for engaging the heart to support the heart when the heart is oriented for surgery and which is located at the base of the heart and which cradles the myocardium of the left ventricle along the arterialventricular groove (AV). Gross support means 400 is shown in
Gross support means 400 supports the mitral valve annulus to maintain competent mitral valve function and head 402 is placed beneath an infolded section of myocardium. Gross support means 400 includes a handle 408 which is attached to head 402 and which extends outside of the patient during surgery for adjusting the location of gross support means head 402.
Head 402 is shown in
As shown in
Using the system 300, a method of performing heart surgery comprises steps of placing frame 300 in the patient, slightly infolding the left atrium of a heart adjacent to the base of the heart, engaging the heart under the edge of the myocardium at the base of the heart with gross support means 400 then using handle 408 tilting and lifting the heart. The heart is engaged near the apex of the heart with suspension head 314 to lift the heart. Such engagement prevents right ventricle collapse. This provides two point support if desired. However, as discussed above, the suspension means alone may be sufficient in some cases to move the heart as necessary. The method can further including a step of using surgery target immobilizing means 340 shown in
Alternative forms of the frame 302 can be used without departing from the scope of the present disclosure, just so the frame is located to move with the patient. Thus, a frame 302′ shown in
Yet another form of the manipulation system of the present invention is shown in
It is understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangements of parts described and shown.